Multiple vulnerabilities in Moodle

1) Improper access control

EUVDB-ID: #VU51480

Risk: Low

CVSSv3.1: 3.8 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-20283

CWE-ID: CWE-284 - Improper Access Control

Exploit availability: No

Description

The vulnerability allows a remote user to gain unauthorized access to otherwise restricted functionality.

The vulnerability exists due to improper access restrictions. The web service responsible for fetching other users' enrolled courses did not validate that the requesting user had permission to view that information in each course. A remote user can gain unauthorized access to the application.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Moodle: 3.5.0 - 3.10.1

External links

http://moodle.org/mod/forum/discuss.php?d=419654

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

2) Stored cross-site scripting

EUVDB-ID: #VU51476

Risk: Medium

CVSSv3.1: 4.7 [CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-20279

CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Exploit availability: No

Description

The disclosed vulnerability allows a remote user to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data passed via the ID number user profile field. A remote user can inject and and execute arbitrary HTML and script code in user's browser in context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Moodle: 3.5.0 - 3.10.1

External links

http://moodle.org/mod/forum/discuss.php?d=419650

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

3) Stored cross-site scripting

EUVDB-ID: #VU51477

Risk: Medium

CVSSv3.1: 5.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-20280

CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Exploit availability: No

Description

The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data passed via feedback answer. A remote attacker can permanently inject and execute arbitrary HTML and script code in user's browser in context of vulnerable website. Note, blind SSRF attack vector is also possible in this case.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Moodle: 3.5.0 - 3.10.1

External links

http://moodle.org/mod/forum/discuss.php?d=419651

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

4) Information disclosure

EUVDB-ID: #VU51478

Risk: Low

CVSSv3.1: 3.8 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-20281

CWE-ID: CWE-200 - Information exposure

Exploit availability: No

Description

The vulnerability allows a remote user to gain access to personal information of website users.

The vulnerability exists due to output of website users' full names via the online users block. A remote user can obtain full names of other website users.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Moodle: 3.5.0 - 3.10.1

External links

http://moodle.org/mod/forum/discuss.php?d=419652

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

5) Authentication bypass using an alternate path or channel

EUVDB-ID: #VU51479

Risk: Medium

CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-20282

CWE-ID: CWE-288 - Authentication Bypass Using an Alternate Path or Channel

Exploit availability: No

Description

The vulnerability allows a remote attacker to bypass authentication process.

The vulnerability exists due to an error that allowed newly created users to bypass email verification process without having an access to the verification email link/secret. A remote attacker can register an account with an email address of other users and gain unauthorized access to the application.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Moodle: 3.5.0 - 3.10.1

External links

http://moodle.org/mod/forum/discuss.php?d=419653

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.